In known hydraulic pressure transformers, the ports in the rotating unit are normally circular in cross-section and the ends of the respective ports in the port plate are normally semi-circular in cross-section. Consequently, as the respective ones of the ports in the rotating unit initiates communication with the respective ones of the slots in the port plate, the opening is small and increase in size to its maximum amount. Since this communication is happening at locations other than top or bottom dead center positions, the instantaneous velocity of the pistons within the rotating unit is high. Likewise, the volume of fluid being received or expelled is high. Since the initial opening is small, the high volume of fluid does not have a free path and the system efficiency is adversely affected.
The present invention is directed to overcoming one or more of the problems as set forth above.